Binder for electrode of lithium rechargeable battery and electrode for rechargeable battery comprising the same

ABSTRACT

In one aspect, a binder for an electrode of a lithium rechargeable battery, which increases adhesion between the electrode and an active material by saving characteristics of two monomers by grafting an acryl group to a vinyl alcohol group, and an electrode for a rechargeable battery comprising the same are provided. The electrode can improve charge and discharge cycle life characteristics of the rechargeable battery.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all priority claims identified in the Application Data Sheet, orany correction thereto, are hereby incorporated by reference under 37CFR 1.57. For example, this application is a continuation in part ofU.S. patent application Ser. No. 13/801,587, filed on Mar. 13, 2013, andclaims priority to and the benefit of Korean Patent Application No.10-2012-0084510, filed on Aug. 1, 2012, in the Korean IntellectualProperty Office, the disclosures of which are incorporated herein byreference in their entireties.

BACKGROUND

1. Field

Embodiments of the present disclosure relate to a binder for anelectrode of a lithium rechargeable battery and an electrode for arechargeable battery comprising the same.

2. Description of the Related Technology

As applications of rechargeable batteries are gradually increasing fromsmall electronic devices to electric automobiles or power storages,there is increasing demand for positive electrode materials for use inrechargeable batteries having various advantageous characteristics,including high safety, extended cycle life, high energy density and highoutput characteristic.

Development of diverse electrode active materials has been made an areaof research. However, there may be a limitation in using known bindersystems, such as SBR/CMC in conjunction with new electrode activematerials due to low adhesion between the binder and certain electrodeactive materials. In addition, the known binders may often adverselyaffect characteristics after repeated charge and discharge cycles. Inparticular, certain active materials may expand to approximately 300% oftheir original sizes due to metal characteristics with repeated chargeand discharge cycles, such as Si-based active materials, thus, there isa limitation in using existing binders. In addition, charge anddischarge characteristics may noticeably degrade when known binders areused.

SUMMARY

Some embodiments provide a binder for an electrode of a lithiumrechargeable battery, which can exhibit high adhesion even when usedwith an electrode active material for a high-capacity battery, therebyproviding excellent charge and discharge cycle life characteristics.

Some embodiments provide a binder for an electrode of a lithiumrechargeable battery, wherein the binder includes a copolymer ofChemical Formula 1:

-   -   wherein L¹ may be

-   -   wherein each R₁ may be independently OH or —OR₅,    -   wherein each R₂ may be independently selected from H (hydrogen),        a substituted or unsubstituted C₁-C₁₀ alkyl group, a substituted        or unsubstituted styrene group, —(C(R₆)₂)_(q)OSi(R₆)₂OR₆,        —(C(R₆)₂)_(q)OSi(R₆)₃, —(C(R₆)₂)_(q)OSi(OR₆)₃,        —(C(R₆)₂)_(q)SiR₆(OR₆)₂, —(C(R₆)₂)_(q)Si(R₆)₂OR₆,        —(C(R₆)₂)_(q)Si(R₆)₃ and —(C(R₆)₂)_(q)Si(OR₆)₃,    -   wherein each R₃ may be independently selected from H (hydrogen),        a substituted or unsubstituted C₁-C₁₀ alkyl group, a substituted        or unsubstituted styrene group, —(C(R₆)₂)_(q)OSiR₆(OR₆)₂,        —(C(R₆)₂)_(q)OSi(R₆)₂OR₆, —(C(R₆)₂)_(q)OSi(R₆)₃,        —(C(R₆)₂)_(q)OSi(OR₆)₃, —(C(R₆)₂)_(q)SiR₆(OR₆)₂,        —(C(R₆)₂)_(q)Si(R₆)₂OR₆, —(C(R₆)₂)_(q)Si(R₆)₃,        —(C(R₆)₂)_(q)Si(OR₆)₃ and a compound of Chemical Formula 3:        —SiR₇R₇—[—O—SiR₇R₇—]_(p)—R₇  Chemical Formula 3    -   wherein at least one of R₂ and R₃ is not H (hydrogen);    -   wherein each R₄ may be independently —OR₁₀ or —NR₁₁R₁₂;    -   wherein R₅ may be —(CHR₂CR₃COR₄)_(m)(CHR₂CHR₃COR₄);    -   wherein each R₆ may be independently selected from H (hydrogen)        or a substituted or unsubstituted C₁-C₂₀ alkyl group, a C₂-C₂₀        alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₁₆ alkyl group, a        C₆-C₂₀ aryl group, and a C₃-C₈ cycloalkyl group;    -   wherein each R₇ may be independently selected from H (hydrogen),        OH, a substituted or unsubstituted C₁-C₂₀ alkyl group, a C₂-C₂₀        alkenyl group, a C₂-C₂₀ alkynyl group, a C₆-C₂₀ aryl group, and        a C₃-C₈ cycloalkyl group, each optionally substituted with one        or more components selected from the group consisting of        halogen, amino, mercapto, ether, ester, C₁-C₂₀ alkoxy, sulfone,        nitro, hydroxy, cyclobutene, carbonyl, carboxyl, alkyd,        urethane, vinyl, nitrile, and epoxy;    -   wherein each R₁₀ may be independently H (hydrogen), a        substituted or unsubstituted C₁-C₁₀ straight or branched alkyl        group, a substituted or unsubstituted C₂-C₂₀ alkenyl group,        C₃-C₈ cycloalkyl group, a substituted or unsubstituted silane        group, a substituted or unsubstituted C₁-C₂₀ alkylsilane group,        or a compound of Chemical Formula 3 as defined above;    -   wherein each R₁₁ and R₁₂ may be independently H (hydrogen), a        substituted or unsubstituted C₁-C₁₀ straight or branched alkyl        group, a substituted or unsubstituted C₂-C₂₀ alkenyl group, or a        substituted or unsubstituted C₃-C₈ cycloalkyl group;    -   wherein x may be an integer between 1 and 5,000,    -   wherein each m may be an integer between 500 and 5,000,    -   wherein each n may be an integer between 500 and 5,000;    -   wherein each p may be an integer between 500 and 5,000;    -   wherein each q may be 0, 1, 2, 3, 4, 5, or 6; and    -   wherein R₅ may be from 30 to 70 wt % of the molecular mass of        the copolymer of Chemical Formula 1.

Some embodiments provide a process for preparing a binder as disclosedand described herein including;

-   -   mixing monomer and polyvinyl alcohol;    -   grafting monomer to polyvinyl alcohol in the presence of an        oxidant to provide the copolymer of Chemical Formula 1,    -   wherein the monomer may be an acryl monomer and a carboxylic        monomer,        -   where the acryl monomer may be at least one selected from            the group consisting of N-methylol acrylamide,            methyl(meth)acrylate, butyl(meth)acrylate, ethyl acrylate,            2-ethyl hexyl acrylate, hydroxypropyl(meth)acrylate,            styrene, alpha-methyl styrene and (meth)acrylonitrile, and        -   where the carboxylic monomer may be at least one selected            from the group consisting of (meth)acrylic acid, itaconic            acid, furmaric acid, crotonic acid, maleic acid, monomethyl            itaconate, methyl fumarate and monobutyl fumarate, which are            used alone or in a combination of two or more of these            materials.

Some embodiments provide a binder for an electrode of a lithiumrechargeable battery, wherein the binder includes a copolymer ofChemical Formula 5:

wherein L¹ may be

wherein R₁ may be OH or —OR₅,

where R₅ may be —(CHR₂CR₃COOR₄)_(m)(CHR₂CHR₃COOR₄) (m may be an integerbetween 500 and 5,000), R₂ and R₃ may be independently H (hydrogen), asubstituted or unsubstituted C1-C10 alkyl group, a substituted orunsubstituted styrene group, or —Si(OR₆)₃, where R₆ may be independentlyH (hydrogen) or a substituted or unsubstituted C1-C20 alkyl group, aC2-C20 alkenyl group, a C2-C20 alkynyl group, a C1-C16 aliphatichydrocarbon group, a C6-C20 aryl group, or C3-C8 cycloalkyl group. Insome embodiments, m may be an integer between 500 and 2,500. In someembodiments, m may be an integer between 500 and 1,000.

In some embodiments, at least one of R₂ and R₃ is not H (hydrogen), R₄is H (hydrogen), a substituted or unsubstituted C1-C10 linear orbranched alkyl group, a substituted or unsubstituted C2-C20 alkenylgroup, a C3-C8 cycloalkyl group, a substituted or unsubstituted silanegroup, or a substituted or unsubstituted C1-C20 alkylsilane group.

In some embodiments, x may be an integer from 1 to about 5000. In someembodiments, the acryl group (R₅) provides 30 to 70 wt % of themolecular mass.

In some embodiments, n may be an integer between 500 and 5,000. In someembodiments, n may be an integer from 1 to about 5,000. In someembodiments, n may be an integer from about 500 and 2,500. In someembodiments, n may be an integer from about 500 and 1,000.

In some embodiments, the copolymer of the of Chemical Formula 1 orChemical Formula 5 has an average molecular weight of 200,000˜500,000.

In some embodiments, the binder further comprises a copolymer ofChemical Formula 6:

wherein L¹ may be

wherein L² may be

-   -   wherein R₂ and R₃ are each independently H (hydrogen), a        substituted or unsubstituted C1-C10 alkyl group, or a        substituted or unsubstituted styrene group, provided at least        one of R₂ and R₃ is not H (hydrogen), and R₄ is H (hydrogen), a        substituted or unsubstituted C1-C10 linear or branched alkyl        group, a substituted or unsubstituted C2-C20 alkenyl group, or a        substituted or unsubstituted C3-C8 cycloalkyl group. In some        embodiments, each R₇ is independently C1-C20 alkyl group, a        C2-C20 alkenyl group, a C2-C20 alkynyl group, a C6-C20 aryl        group, or a C3-C8 cycloalkyl group, each optionally substituted        with one or more components selected from the group consisting        of halogen, amino, mercapto, ether, ester, C1-C20 alkoxy,        sulfone, nitro, hydroxy, cyclobutene, carboxyl, alkyd, urethane,        vinyl, and nitrile. In some embodiments, y may be an integer        from 1 to about 5000.

Some embodiments provide an electrode for a rechargeable battery usingthe electrode active material as disclosed and described herein.

As described above, in the binder according to the present invention, anacryl group is grafted to a vinyl alcohol group to improve thecharacteristics of the binder, such as adhesion. In addition, since thenumber of cross links is increased, the binder may have a densestructure, so that it can withstand expansion of an electrode activematerial.

In some embodiments, the binder may have a silane moiety as part of anacryl group, by which a netting property is considerably strengthened byincreasing the kinds and lengths of branches, thereby improving adhesionbetween the electrode and the active material.

Therefore, the rechargeable battery including an electrode employing thebinder according to the present embodiments may demonstrate good chargeand discharge cycle life characteristics.

Additional embodiments and their advantages are set forth in part in thedescription which follows and may be learned by practice of theinvention.

Some embodiments provide a process for preparing a binder as disclosedand described herein including;

-   -   mixing monomer and polyvinyl alcohol;    -   grafting monomer to polyvinyl alcohol in the presence of an        oxidant to provide the copolymer of Chemical Formula 1,    -   wherein the monomer may be an acryl monomer and a carboxylic        monomer,        -   where the acryl monomer may be at least one selected from            the group consisting of N-methylol acrylamide,            methyl(meth)acrylate, butyl(meth)acrylate, ethyl acrylate,            2-ethyl hexyl acrylate, hydroxypropyl(meth)acrylate,            styrene, alpha-methyl styrene and (meth)acrylonitrile, and        -   where the carboxylic monomer may be at least one selected            from the group consisting of (meth)acrylic acid, itaconic            acid, furmaric acid, crotonic acid, maleic acid, monomethyl            itaconate, methyl fumarate and monobutyl fumarate, which are            used alone or in a combination of two or more of these            materials.

Some embodiments provide process for preparing a binder including acopolymer of Chemical Formula 5 comprising:

-   -   mixing acryl monomer and polyvinyl alcohol;    -   grafting acryl monomer to polyvinyl alcohol in the presence of        an oxidant, where the acryl monomer may be at least one monomer        selected from the group consisting of methyl(meth)acrylate,        butyl(meth)acrylate, ethyl acrylate, 2-ethyl hexyl acrylate,        hydroxypropyl(meth)acrylate, styrene, alpha-methyl styrene and        (meth)acrylonitrile to provide the binder including the        copolymer of Chemical Formula 5

-   -   wherein L¹ may be

-   -    wherein R₁ may be OH or —OR₅, where R₅ may be        —(CHR₂CR₃COOR₄)_(m)(CHR₂CHR₃COOR₄) (m may be an integer between        500 and 5,000), R₂ and R₃ may each be independently H        (hydrogen), a substituted or unsubstituted C1-C10 alkyl group, a        substituted or unsubstituted styrene group, or —Si(OR₆)₃, where        R₆ may be independently H (hydrogen) or a substituted or        unsubstituted C1-C20 alkyl group, a C2-C20 alkenyl group, a        C2-C20 alkynyl group, a C1-C16 alkyl group, a C6-C20 aryl group,        C3-C8 cycloalkyl group, wherein at least one of R₂ and R₃ is not        H (hydrogen), R₄ may be H (hydrogen), a substituted or        unsubstituted C1-C10 linear or branched alkyl group, a        substituted or unsubstituted C2-C20 alkenyl group, a C3-C8        cycloalkyl group, a substituted or unsubstituted silane group,        or a substituted or unsubstituted C1-C20 alkylsilane group, x        may be an integer between 1 and 5,000, and n may be an integer        between 500 and 5,000. In some embodiments, the oxidant may be        ammonium persulfate.

BRIEF DESCRIPTION OF THE DRAWINGS

The aspects, features and advantages of the present embodiments will bemore apparent from the following detailed description in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a partially cross-sectional view of a lithium rechargeablebattery according to an embodiment;

FIG. 2 is an infrared (IR) spectrum of a binder according to PreparationExample 1;

FIG. 3 is an infrared (IR) spectrum of a binder according to PreparationExample 3; and

FIG. 4 is an infrared (IR) spectrum of a binder according to PreparationExample 4.

DETAILED DESCRIPTION

Hereinafter, certain embodiments will be described in detail withreference to the accompanying drawings.

Binder

In some embodiments, the binder for an electrode of a rechargeablebattery may include a polymer including Chemical Formula 1:

-   -   wherein L¹ may be

-   -   wherein each R₁ may be independently OH or —OR₅,    -   wherein each R₂ may be independently selected from H (hydrogen),        a substituted or unsubstituted C₁-C₁₀ alkyl group, a substituted        or unsubstituted styrene group, —(C(R₆)₂)_(q)OSi(R₆)₂OR₆,        —(C(R₆)₂)_(q)OSi(R₆)₃, —(C(R₆)₂)_(q)OSi(OR₆)₃,        —(C(R₆)₂)_(q)SiR₆(OR₆)₂, —(C(R₆)₂)_(q)Si(R₆)₂OR₆,        —(C(R₆)₂)_(q)Si(R₆)₃ and —(C(R₆)₂)_(q)Si(OR₆)₃,    -   wherein each R₃ may be independently selected from H (hydrogen),        a substituted or unsubstituted C₁-C₁₀ alkyl group, a substituted        or unsubstituted styrene group, —(C(R₆)₂)_(q)OSiR₆(OR₆)₂,        —(C(R₆)₂)_(q)OSi(R₆)₂OR₆, —(C(R₆)₂)_(q)OSi(R₆)₃,        —(C(R₆)₂)_(q)OSi(OR₆)₃, —(C(R₆)₂)_(q)SiR₆(OR₆)₂,        —(C(R₆)₂)_(q)Si(R₆)₂OR₆, —(C(R₆)₂)_(q)Si(R₆)₃,        —(C(R₆)₂)_(q)Si(OR₆)₃ and a compound of Chemical Formula 3:        —SiR₇R₇—[—O—SiR₇R₇—]_(p)—R₇  Chemical Formula 3    -   wherein at least one of R₂ and R₃ is not H (hydrogen);    -   wherein each R₄ may be independently —OR₁₀ or —NR₁₁R₁₂;    -   wherein R₅ may be —(CHR₂CR₃COR₄)_(m)(CHR₂CHR₃COR₄);    -   wherein each R₆ may be independently selected from H (hydrogen)        or a substituted or unsubstituted C₁-C₂₀ alkyl group, a C₂-C₂₀        alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₁₆ alkyl group, a        C₆-C₂₀ aryl group, and a C₃-C₈ cycloalkyl group;    -   wherein each R₇ may be independently selected from H (hydrogen),        OH, a substituted or unsubstituted C₁-C₂₀ alkyl group, a C₂-C₂₀        alkenyl group, a C₂-C₂₀ alkynyl group, a C₆-C₂₀ aryl group, and        a C₃-C₈ cycloalkyl group, each optionally substituted with one        or more components selected from the group consisting of        halogen, amino, mercapto, ether, ester, C₁-C₂₀ alkoxy, sulfone,        nitro, hydroxy, cyclobutene, carbonyl, carboxyl, alkyd,        urethane, vinyl, nitrile, and epoxy;    -   wherein each R₁₀ may be independently H (hydrogen), a        substituted or unsubstituted C₁-C₁₀ straight or branched alkyl        group, a substituted or unsubstituted C₂-C₂₀ alkenyl group,        C₃-C₈ cycloalkyl group, a substituted or unsubstituted silane        group, a substituted or unsubstituted C₁-C₂₀ alkylsilane group,        or a compound of Chemical Formula 3 as defined above;    -   wherein each R₁₁ and R₁₂ may be independently H (hydrogen), a        substituted or unsubstituted C₁-C₁₀ straight or branched alkyl        group, a substituted or unsubstituted C₂-C₂₀ alkenyl group, or a        substituted or unsubstituted C₃-C₈ cycloalkyl group;    -   wherein x may be an integer between 1 and 5,000,    -   wherein each m may be an integer between 500 and 5,000,    -   wherein each n may be an integer between 500 and 5,000;    -   wherein each p may be an integer between 500 and 5,000;    -   wherein each q may be 0, 1, 2, 3, 4, 5, or 6; and    -   wherein R₅ may be from 30 to 70 wt % of the molecular mass of        the copolymer of Chemical Formula 1. In some embodiments, each q        may be 0. In some embodiments, each q may be 1. In some        embodiments, each q may be 2. In some embodiments, each q may        be 0. In some embodiments, each q may be 1. In some embodiments,        each q may be 2.

In some embodiments, each R₃ may be Chemical Formula 3:—SiR₇R₇—[—O—SiR₇R₇—]_(p)—R₇  Chemical Formula 3

-   -   wherein each R₇ may be independently H (hydrogen), OH, a        substituted or unsubstituted C₁-C₂₀ alkyl group, a C₂-C₂₀        alkenyl group, a C₂-C₂₀ alkynyl group, a C₆-C₂₀ aryl group, or a        C₃-C₈ cycloalkyl group, each optionally substituted with one or        more components selected from the group consisting of halogen,        amino, mercapto, ether, ester, C₁-C₂₀ alkoxy, sulfone, nitro,        hydroxy, cyclobutene, carbonyl, carboxyl, alkyd, urethane,        vinyl, nitrile, and epoxy;    -   each R₄ may be —OR₁₀; and each R₁₀ may be a compound of Chemical        Formula 3.

In some embodiments, the binder may be made by a process including:

-   -   grafting monomer to polyvinyl alcohol, wherein the monomer may        be an acryl monomer and a carboxylic monomer,        -   where the acryl monomer may be at least one selected from            the group consisting of N-methylol acrylamide,            methyl(meth)acrylate, butyl(meth)acrylate, ethyl acrylate,            2-ethyl hexyl acrylate, hydroxypropyl(meth)acrylate,            styrene, alpha-methyl styrene and (meth)acrylonitrile; and        -   where the carboxylic monomer may be at least one selected            from the group consisting of (meth)acrylic acid, itaconic            acid, furmaric acid, crotonic acid, maleic acid, monomethyl            itaconate, methyl fumarate and monobutyl fumarate, which are            used alone or in a combination of two or more of these            materials.

In some embodiments, the binder further includes a copolymer of ChemicalFormula 2:

-   -   wherein L¹ may be

-   -   wherein L² may be

-   -   y may be an integer from 1 to about 5000;    -   wherein R₂ and R₃ may each independently be H (hydrogen), a        substituted or unsubstituted C₁-C₁₀ alkyl group, or a        substituted or unsubstituted styrene group, provided at least        one of R₂ and R₃ is not H (hydrogen), and R₄ is H (hydrogen), a        substituted or unsubstituted C₁-C₁₀ linear or branched alkyl        group, a substituted or unsubstituted C₂-C₂₀ alkenyl group, or a        substituted or unsubstituted C₃-C₈ cycloalkyl group.

In some embodiments, each R₂ may be independently selected from H(hydrogen), a substituted or unsubstituted C₁-C₁₀ alkyl group, asubstituted or unsubstituted styrene group, and —Si(OR₆)₃. In someembodiments, each R₃ may be independently selected from H (hydrogen), asubstituted or unsubstituted C₁-C₁₀ alkyl group, a substituted orunsubstituted styrene group, —Si(OR₆)₃ and a compound of ChemicalFormula 3:—SiR₇R₇—[—O—SiR₇R₇—]_(p)—R₇  Chemical Formula 3

In some embodiments, each R₁₁ and R₁₂ may be independently H (hydrogen),a substituted or unsubstituted C₁-C₁₀ straight or branched alkyl group,a substituted or unsubstituted C₂-C₂₀ alkenyl group, or C₃-C₈ cycloalkylgroup.

In some embodiments, the binder for an electrode of a rechargeablebattery may include a polymer including Chemical Formula 5:

wherein L¹ may be

wherein R₁ may be OH or —OR₅, where R₅ may be—(CHR₂CR₃COOR₄)_(m)(CHR₂CHR₃COOR₄) (m may be an integer between 500 and5,000), R₂ and R₃ may be independently H (hydrogen), a substituted orunsubstituted C1-C10 alkyl group, a substituted or unsubstituted styrenegroup, or —Si(OR₆)₃, where R₆ is independently H or a substituted orunsubstituted C1-C20 alkyl group, a C2-C20 alkenyl group, a C2-C20alkynyl group, a C1-C16 aliphatic hydrocarbon group, a C6-C20 arylgroup, or C3-C8 cycloalkyl group. In some embodiments, m may be aninteger between 500 and 2,500. In some embodiments, m may be an integerbetween 500 and 1,000.

In some embodiments, at least one of R₂ and In some embodiments, at isnot H (hydrogen), R₄ is H (hydrogen), a substituted or unsubstitutedC1-C10 linear or branched alkyl group, a substituted or unsubstitutedC2-C20 alkenyl group, a C3-C8 cycloalkyl group, a substituted orunsubstituted silane group, or a substituted or unsubstituted C1-C20alkylsilane group.

In some embodiments, x may be an integer from 1 to about 5000. In someembodiments, the acryl group ( ) provides 30 to 70 wt % of the molecularmass.

In some embodiments, n may be an integer between 500 and 5,000. In someembodiments, n may be an integer from 1 to about 5,000. In someembodiments, n may be an integer from about 500 and 2,500. In someembodiments, n may be an integer from about 500 and 1,000.

In some embodiments, the polymer including Chemical Formula 1 mayinclude a polymer of Chemical Formula 2:

-   -   wherein L¹ may be

-   -   wherein L² may be

-   -   y may be an integer from 1 to about 5000; and    -   wherein R₂ and R₃ may each independently be H (hydrogen), a        substituted or unsubstituted C₁-C₁₀ alkyl group, or a        substituted or unsubstituted styrene group, provided at least        one of R₂ and R₃ is not H (hydrogen), and R₄ is H (hydrogen), a        substituted or unsubstituted C₁-C₁₀ linear or branched alkyl        group, a substituted or unsubstituted C2-C20 alkenyl group, or a        substituted or unsubstituted C₃-C₈ cycloalkyl group.

In some embodiments, the polymer including Chemical Formula 5 mayinclude a polymer of Chemical Formula 6:

wherein L¹ may be

wherein L² may be

wherein R₂ and R₃ may be independently H (hydrogen), a substituted orunsubstituted C1-C10 alkyl group, or a substituted or unsubstitutedstyrene group, provided at least one of R₂ and R₃ is not H (hydrogen),and R₄ may be H (hydrogen), a substituted or unsubstituted C1-C10 linearor branched alkyl group, a substituted or unsubstituted C2-C20 alkenylgroup, or a substituted or unsubstituted C3-C8 cycloalkyl group.

In some embodiments, a silane group having a hydrolysis group may beused in the preparation of the polymer to afford a moiety within thepolymer as specified by Chemical Formula 3:

wherein each R₇ is independently H (hydrogen), OH, a substituted orunsubstituted C1-C20 alkyl group, a C2-C20 alkenyl group, a C2-C20alkynyl group, a C1-C16 aliphatic hydrocarbon group, a C6-C20 arylgroup, or a C3-C8 cycloalkyl group, and R₇ may have at least onefunctional group selected from the group consisting of halogen, amino,mercapto, ether, ester, C1-C20 alkoxy, sulfone, nitro, hydroxy,cyclobutene, carbonyl, carboxyl, alkyd, urethane, vinyl, nitrile, andepoxy.

In some embodiments, the copolymer including Chemical Formula 1 orChemical Formula 5 has a weight average molecular weight of 200,000 to500,000. If the weight average molecular weight of the copolymerincluding Chemical Formula 1 or Chemical Formula 5 is less than 200,000,the effects of increased adhesion and improving charge and dischargecycle life characteristic are not noticeable. If the weight averagemolecular weight of the copolymer of Chemical Formula 1 or ChemicalFormula 5 is greater than 500,000, gelation may be likely to occurduring polymerization.

In some embodiments, in the copolymer including Chemical Formula 1 orChemical Formula 5, n and y may have a ratio of 1:2.3 to 2.3:1. Theacryl group may be effectively grafted to the vinyl alcohol group withinthe preceeding range.

In some embodiments, the binder may be prepared by grafting an acrylmonomer to polyvinyl alcohol having many hydroxyl groups. In someembodiments, the monomer used in grafting may include at least onecomponent selected from the group consisting of methyl(meth)acrylate,and butyl(meth)acrylate, ethyl acrylate, 2-ethyl hexyl acrylate,hydroxypropyl(meth)acrylate, styrene, alpha-methyl styrene, and at leastone carboxylic monomer selected from the group consisting of(meth)acrylic acid, itaconic acid, furmaric acid, crotonic acid, maleicacid, monomethyl itaconate, methyl fumarate and monobutyl fumarate,which are used alone or a combination of two or more of these materials.In addition, in the present invention, examples of the comonomercopolymerizable with the acryl monomer may include not only carboxylicmonomer, (meth)acrylamide, diacetone(meth)acrylamide,N-methylol(meth)acrylamide, N-isobutoxy(meth)acrylamide, acrylonitrileand methacrylonitrile.

In some embodiments, the monomer may be present in an amount of 70 to 98wt % based on the total weight of the monomers used, and the graftedacryl group has a glass transition temperature (Tg) in a range of 0 to70° C.

In some embodiments, the polymerization for preparing the binder may beinitiated by heat or a redox initiating process. In order to increasethe grafting efficiency, a redox initiating process is preferred. Insome embodiments, a general free-radical initiator such ashydroperoxide, benzoyl peroxide, t-butyl hydroperoxide, ammonium oralkali persulfate may be used as the initiator, and a low-level ionizedsalt such as sulfite, hydrogen sulfite, iron, copper or cobalt, anorganic amine such as N,N,N,N′-tetramethylethylenediamine or aniline,and a reducing sugar such as aldose or ketose may be used as a reducingagent. In some embodiments, ceric ammonium nitrate or a transition metalsuch as nickel or copper may also be used as an additional component. Insome embodiments, the initiator may be generally present in an amount of0.05 to 3.0 wt % based on the total weight of monomer used.

In some embodiments, the binder may use a cross-linking agent to inducecross linking between grafted acryl chains so as to withstand expansionof an electrode active material. Examples of usable cross-linking agentsmay include diethylene glycol diacrylate, triethylene glycoltriacrylate, tripropylene triacrylate, 1,6-hexanedioldiacrylate,trimethylpropane triacrylate, divinyl benzene, and diallylphthalate, andmay be used in an amount of 0.2 to 5 wt % based on the total weight ofthe monomer used.

In some embodiments, the binder according to the present invention mayintroduce a silane group in order to improve adhesion between anelectrode and an active material. In some embodiments, the adhesion ofthe binder may be adversely affected due to volumetric expansion duringcharge and discharge cycles, thereby degrading the charge and dischargecycle life characteristics in a case of a Si-based negative electrodeactive material. Binding between the binder and the active material isinduced, thereby improving the cycle life characteristic. In someembodiments, the cycle life characteristic of the battery can beimproved by a covalent bond between an OH functional group on a surfaceof the Si-based negative electrode active material and a silanolfunctional group grafted to the binder. In some embodiments, the binderhaving a siloxane bond may be prepared using silane having anethylenically unsaturated monomer capable of binding with the acrylmonomer and silane having a hydrolysis group in order to synthesize thesilane grafted binder. Examples of the silane having the ethylenicallyunsaturated monomer may include vinyltrimethoxy silane, vinyltriethoxysilane, 3-(meth)acryloxypropyl trimethoxy silane, 3-(meth)acryloxypropyltriethoxy silane, 3-acryloxypropyl trimethoxy silane, and3-acryloxypropyl triethoxy silane. Specific examples of the silanehaving a hydrolysis group may include at least one selected from thegroup consisting of methyltrimethoxy silane, phenyltrimethoxysilane,methyltriethoxysilane, phenyltriethoxysilane, isobutyltrimethoxysilane,and dimethyldimethoxysilane. In some embodiments, the silane may becontained in an amount of 5-30 wt % based on the total weight of theacryl monomer used.

In some embodiments, a surfactant may be used in order to attainstability of the binder. Examples of suitable surfactants may include ananionic surfactant, a nonionic surfactant and a combination thereof.Examples of the anionic surfactant used in the present invention mayinclude aliphatic rosin, salts of naphthenic acid, naphthalene sulfonicacid having a low molecular weight, a condensed product of formaldehyde,a carboxylic polymer, a copolymer appropriately balanced inhydrophilicity and oleophilicity, alkali metal or ammonium alkylsulfate, alkylsulfonic acid, alkyl phosphonic acid, fatty acid,oxyethylated alkylphenol sulfate, phosphate, and a reactive anionicemulsifier having an unsaturated double bond polymerizable with apolymer chain. Examples of the nonionic surfactant used in the presentinvention may include alkylphenol ethoxylate, polyoxyethylenicalkylalcohol, amine polyglycol condensate, modified polyethoxy additive,long chain carboxylic ester, modified alkylaryl ether, alkyl polyetheralcohol, and a reactive nonionic emulsifier having an unsaturated doublebond polymerizable with a polymer chain. In some embodiments, theanionic surfactants and the nonionic surfactants may be used alone orcombinations of two or more of the surfactants listed herein. Forexample, the reactive emulsifier may be more preferably used and may becontained in an amount of 0.1 to 3 wt % based on the weight of thepolymerized monomer.

In some embodiments, the binder may also be used in combination with theconventional binder such as styrene butadiene rubber (SBR) orcarboxylmethylcellulose (CMC). In some embodiments, the binder may becontained in an amount of 1 wt % or greater. In some embodiments, thebinder may further include additional functional additives such as epoxyresin, oxirand triazines, polyvalent metal salts, amino formaldehyderesins or isocyanates, to induce cross-linkage between the carboxylfunctional group or hydroxy functional group in the binder, therebyincreasing bonds between polymer chains.

Other Additives

In some embodiments, a composition of the binder may further includeadditives in addition to the soluble polymer binder, in order to improvethe performance of further characteristics.

Examples of the additives may include a dispersing agent, a thickeningagent, a conductive agent, a filler and so on.

In some embodiments, the respective additives may be used after beingpre-mixed with a binder composition for forming the electrode when aslurry for forming an electrode is prepared, or may be independentlyused after being separately prepared.

Components of the additives to be used are determined by the activematerial and binder components, or the additives may not be used.

In some embodiments, the content of the additive may vary according tothe kind of the active material, the components of the binder and thekind of the additive used. In some embodiments, the additive may bepreferably used in an amount of 0.1 to 10 wt % based on the weight ofthe binder composition, excluding a solvent. If the content of theadditive is less than 0.1 wt %, the effect of the additive used is notsufficient. If the content of the additive is greater than 10 wt %, aproportion of the content of the binder to that of the bindercomposition for forming a negative electrode is reduced, so that it isdifficult to attain desired characteristics.

In some embodiments, the dispersing agent may be selected amongmaterials of improving dispersibility of the positive or negativeelectrode active materials and the conductive agent in the slurry tothen be used. In some embodiments, the dispersing agent may be selectedfrom the cationic, anionic, or nonionic dispersing agents to then beused. In some embodiments, the dispersing agent may be at least oneselected among compounds having in their lipophilic parts a C5-C20hydrocarbon, an acryl oligomer, an ethylene oxide and propylene oxideoligomer, an ethylene oxide and propylene oxide oligomer, and a urethaneoligomer.

In some embodiments, a thickening agent may be added when the viscosityof the slurry is low, thereby facilitating a coating process of theslurry on a current collector. Examples of the thickening agent mayinclude at least one component selected from the group consisting ofcarboxymethyl cellulose, carboxyethyl cellulose, ethyl cellulose,hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropylcellulose, and polyvinyl alcohol.

However, the dispersing agent and the thickening agent are preferablyused in small amounts only when necessary.

In some embodiments, the conductive agent may be used to further improvea conductive path of an electrode. In some embodiments, the conductiveagent may be used to impart conductivity to the electrode and anyelectronic conducting material that does not induce a chemical change inbatteries may be used. Examples of the conductive agent may include atleast one conductive material, such as natural graphite, artificialgraphite, carbon black, acetylene black, ketchen black, carbon fiber,and the like, and metal powder, such as copper (Cu), nickel (Ni),aluminum (Al), silver (Ag), and the like.

The filler is a supplementary ingredient to inhibit electrode expansionby improving the strength of the binder, and examples thereof mayinclude at least one fibrous material, such as a glass fiber, a carbonfiber or a metal fiber.

Electrode

In some embodiments, the electrode may include an electrode activematerial and the binder as disclosed and described herein. In someembodiments, the electrode may be formed by coating an electrode slurryincluding the electrode active material, the binder and a solvent mixedtherein, and, if necessary, further including a conductive agent, on anelectrode current collector to a predetermined thickness, drying andcompressing the same.

In some embodiments, the binder may be preferably used in preparing anegative electrode.

In some embodiments, any negative electrode active material that iscapable of intercalating and deintercalating lithium ions can be used asthe negative electrode active material used in preparing the negativeelectrode.

In some embodiments, the negative electrode active material may includeone or more material selected from the group consisting of compoundsthat can reversibly intercalate and deintercalate lithium ions, metalsbeing capable of alloying with lithium, and combinations thereof. Insome embodiments, the materials that can reversibly intercalate anddeintercalate lithium ions may include at least one selected from thegroup consisting of artificial graphite, natural graphite, graphitizedcarbon fiber, graphitized mesocarbon microbeads, fullerene, amorphouscarbon, and so on.

In some embodiments, the amorphous carbon may be a hard carbon, cokes,or a soft carbon obtained by firing at a temperature of 1500° C. orbelow, such as mesocarbon microbead (MCMB) or mesophase pitch-basedcarbon fiber (MPCF). In addition, examples of suitable metals beingcapable of alloying with lithium include at least one metal selectedfrom the group consisting of aluminum (Al), silicon (Si), tin (Sn), lead(Pb), zinc (Zn), bismuth (Bi), indium (In), magnesium (Mg), gallium(Ga), cadmium (Cd), and germanium (Ge), which may be used alone or incombinations. In addition, the metals may be used in combinations withcarbonaceous materials.

In some embodiments, the negative electrode active material may bepreferably a Si-based negative electrode active material. In someembodiments, the Si-based negative electrode active material may ensurea high capacity but may adversely affect the adhesion of the binder dueto excessive expansion during charge and discharge cycles, therebylowering cycle life characteristics of battery. However, thedisadvantage can be overcome by using the binder according to thepresent embodiments. In some embodiments, the binder may provide arechargeable battery ensuring a high capacity and excellent cycle lifecharacteristics.

In some embodiments, the Si-based negative electrode active material mayinclude one or more elements based on SiOx (0≦x<2) or Si, the one ormore elements selected from the group consisting of Group 2A, 3A and 4Aelements and transition metals. In some embodiments, the elements may bepreferably at least one of Sn, Al, Pb, In, Ni, Co, Ag, Mn, Cu, Ge, Cr,Ti and Fe, more preferably at least one of Ni and Ti, and mostpreferably Ni and Ti.

In some embodiments, the Si-based metal alloy including Ni and Ti may bepreferably contained in an amount of 55 to 85 at % based on the totalweight of the metal alloy because the Si-based metal alloy may be usedas a Si-based active material and provide sufficiently high charge anddischarge capacity when it is used within this range.

In some embodiments, the metal elements are preferably contained in aratio of 16:17:17 at % when the Si metal alloy is a Si:Ni:Ti alloy.Within this range, excellent capacity and cycle life characteristics aredemonstrated.

The metal alloy may be prepared by well known processes in the relatedart, including, for example, melting spinning, atomizing, mechanicallyalloying, and so on.

Non-limiting examples of the negative electrode current collector mayinclude a punching metal, an X-punching metal, gold foil, a metal foam,a net metal fiber sinter, a nickel foil, a copper foil, and so on.

In some embodiments, compounds that can reversibly intercalate anddeintercalate lithium ions, which are referred to as lithiatedintercalation compounds, may be used as the positive electrode activematerial for forming the positive electrode according to the presentinvention. In some embodiments, the lithiated intercalation compound maybe at least one composite oxide of a metal selected from cobalt (Co),nickel (Ni) and a combination thereof and lithium. In some embodiments,the lithiated intercalation compound may include a compound representedby the following Chemical Formulas:

Li_(a)A_(1-b)X_(b)D¹ ₂ (0.90≦a≦1.8, 0≦b≦0.5);

-   Li_(a)E_(1-b)X_(b)O_(2-c)D¹ _(c) (0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05);-   LiE_(2-b)X_(b)D¹ ₄ (0≦b≦0.5); LiE_(2-b)X_(b)O_(4-c)D¹ _(c) (0≦b≦0.5,    0≦c≦0.05);-   Li_(a)Ni_(1-b-c)C_(ob)X_(c)D_(α) (0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05,    0≦α≦2);-   Li_(a)Ni_(1-b-c)C_(ob)X_(c)O_(2-α)T_(α) (0.90≦a≦1.8, 0≦b≦0.5,    0≦c≦0.05, 0≦α≦2);-   Li_(a)Ni_(1-b-c)C_(ob)X_(c)O_(2-α)T₂ (0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05,    0≦a≦2);-   Li_(a)Ni_(1-b-c)Mn_(b)X_(c)D¹ _(α) (0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05,    0≦α≦2);-   Li_(a)Ni_(1-b-c)Mn_(b)X_(c)O_(2-α)T_(α) (0.90≦a≦1.8, 0≦b≦0.5,    0≦c≦0.05, 0≦α≦2);-   Li_(a)Ni_(1-b-c)Mn_(b)X_(c)O_(2-α)T₂ (0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05,    0≦α≦2);-   Li_(a)Ni_(b)E_(c)G_(d)O₂ (0.90≦a≦1.8, 0≦b≦0.9, 0≦c≦0.5,    0.001≦d≦0.1);-   Li_(a)Ni_(b)Co_(c)Mn_(d)G_(e)O₂ (0.90≦a≦1.8, 0≦b≦0.9, 0≦c≦0.5,    0≦d≦0.5, 0.001≦e≦0.1);-   Li_(a)NiG_(b)O₂ (0.90≦a≦1.8, 0.001≦b≦0.1); Li_(a)CoG_(b)O₂    (0.90≦a≦1.8, 0.001≦b≦0.1);-   Li_(a)MnG_(b)O₂ (0.90≦a≦1.8, 0.001≦b≦0.1);-   Li_(a)Mn₂G_(b)O₂ (0.90≦a≦1.8, 0.001≦b≦0.1);-   QO₂, QS₂; LiQS₂; V₂O₅, LiV₂O₅; LiZO₂; LiNiVO₄; Li_((3-f))J₂(PO₄)₃    (0≦f≦2); Li_((3-f))Fe₂(PO₄)₃ (0≦f≦2); LiFePO₄

In the above formulae, A is selected from the group consisting of Ni,Co, Mn, and combinations thereof; X is selected from the groupconsisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element,and combinations thereof; D¹ is selected from the group consisting of O(oxygen), F (fluorine), S (sulfur), P (phosphorus), and combinationsthereof; E is selected from the group consisting of Co, Mn, andcombinations thereof; T is selected from the group consisting of F(fluorine), S (sulfur), P (phosphorus), and combinations thereof; G isselected from the group consisting of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V,and combinations thereof; Q is selected from the group consisting of Ti,Mo, Mn, and combinations thereof; Z is selected from the groupconsisting of Cr, V, Fe, Sc, Y, and combinations thereof; and J isselected from the group consisting of V, Cr, Mn, Co, Ni, Cu, andcombinations thereof.

In some embodiments, the compound may have a coating layer on thesurface, or may be mixed with another compound having a coating layer.In some embodiments, the coating layer may include at least one coatingelement compound selected from the group consisting of an oxide of acoating element, a hydroxide of a coating element, an oxyhydroxide of acoating element, an oxycarbonate of a coating element, and a hydroxylcarbonate of a coating element. In some embodiments, the compound forthe coating layer may be amorphous or crystalline. In some embodiments,the coating element included in the coating layer may include Mg, Al,Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixtures thereof.In some embodiments, the coating layer may be disposed with a methodhaving no adverse influence on properties of a positive active material.For example, the method may include any coating method such as spraycoating, dipping, and the like, but is not illustrated in more detailsince it is well-known to those of ordinary skill in the art.

Unless otherwise indicated, the term “substituted,” refers to a group inwhich, one, or more than one of the hydrogen atoms has been replacedwith one or more group(s) individually and independently selected from:alkyl, alkenyl, cycloalkenyl, alkynyl, heteroalkyl, haloalkyl,cycloalkyl, aryl, alkenylO—, arylO—, alkenylO—, cycloalkylC(═O)—,arylC(═O)—, arylC(═O)NH—, arylNHC(═O)—, aryl(CH₂)₀₋₃O(CH₂)₀₋₃—,HO(CH₂)₁₋₃NH—, HO(CH₂)₁₋₃O—, HO(CH₂)₁₋₃—, HO(CH₂)₁₋₃O(CH₂)₁₋₃—,—C(═O)NHNH₂, heteroaryl, hydroxy, alkoxy, mercapto, cyano, halo, oxo,O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido,N-amido, S-sulfonamido, N-sulfonamido, C-carboxy, O-carboxy, isocyanato,thiocyanato, isothiocyanato, nitro, trihalomethanesulfonyl, and amino.

The term “O-carboxy” refers to the group consisting of formula RC(═O)O—,covalently bonded to the parent molecule through an —O— linkage.

The term “C-carboxy” refers to the group consisting of formula —C(═O)OR,covalently bonded to the parent molecule through a —C— linkage.

The substituent “R” appearing by itself and without a number designationrefers to a substituent selected from alkyl, cycloalkyl, aryl, andheteroaryl (bonded through a ring carbon).

The term “isocyanato” refers to the group consisting of formula —NCO,covalently bonded to the parent molecule through a —N— linkage.

The term “thiocyanato” refers to the group consisting of formula —CNS,covalently bonded to the parent molecule through a —C— linkage.

The term “isothiocyanato” refers to the group consisting of formula—NCS, covalently bonded to the parent molecule through a —N— linkage.

The term “sulfonyl” refers to the group consisting of formula —S(═O)—R,covalently bonded to the parent molecule through a —S— linkage.

The term “sulfone” refers to the group consisting of formula —S(═O)₂—R,covalently bonded to the parent molecule through a —S— linkage.

The term “S-sulfonamido” refers to the group consisting of formula—S(═O)₂NR, covalently bonded to the parent molecule through a —S—linkage.

The term “N-sulfonamido” refers to the group consisting of formulaRS(═O)₂NH—, covalently bonded to the parent molecule through a —N—linkage.

The term “O-carbamyl” refers to the group consisting of formula—OC(═O)—NR, covalently bonded to the parent molecule through a —O—linkage.

The term “N-carbamyl” refers to the group consisting of formulaROC(═O)NH—, covalently bonded to the parent molecule through a —N—linkage.

The term “O-thiocarbamyl” refers to the group consisting of formula—OC(═S)—NR, covalently bonded to the parent molecule through a —O—linkage.

The term “N-thiocarbamyl” refers to the group consisting of formulaROC(═S)NH—, covalently bonded to the parent molecule through a —N—linkage.

The term “C-amido” refers to the group consisting of formula —C(═O)—NR₂,covalently bonded to the parent molecule through a —C— linkage.

The term “N-amido” refers to the group consisting of formula RC(═O)NH—,covalently bonded to the parent molecule through a —N— linkage.

The term “oxo” refers to the group consisting of formula ═O.

The term “amide” refers to a chemical moiety with formula—(R)_(n)—C(═O)NHR′ or —(R)_(n)—NHC(═O)R′, covalently bonded to theparent molecule through a —C— or —N— linkage, where R is selected fromalkyl, cycloalkyl, aryl, and heteroaryl (bonded through a ring carbon),where n is 0 or 1 and R′ is selected from hydrogen, alkyl, cycloalkyl,aryl, and heteroaryl (bonded through a ring carbon).

The term “amino” refers to a chemical moiety with formula —NHR′R″,covalently bonded to the parent molecule through a —N— linkage, where R′and R″ are each independently selected from hydrogen, alkyl, cycloalkyl,aryl, heteroaryl (bonded through a ring carbon) and heteroalicyclic(bonded through a ring carbon).

As used herein, the term “ester” refers to the group consisting offormula —C(═O)OR, covalently bonded to the parent molecule through a —C—linkage, where R is selected from alkyl, cycloalkyl, aryl, andheteroaryl (bonded through a ring carbon).

As used herein, the term “ether” refers to the group consisting offormula —CR′R″OR, covalently bonded to the parent molecule through a —C—linkage, where R is selected from alkyl, cycloalkyl, aryl, andheteroaryl (bonded through a ring carbon), and R′ and R″ are eachindependently selected from hydrogen, alkyl, and cycloalkyl.

As used herein, the term “alkyl” refers to a branched or unbranchedfully saturated aliphatic hydrocarbon group. In some embodiments, alkylsmay be substituted or unsubstituted. Alkyls include, but are not limitedto, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl,pentyl, hexyl, cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl and thelike, each of which may be optionally substituted in some embodiments.In some embodiments, the alkyl may have C1 to C6 carbon atoms. Forexample, C₁₋₆alkyl includes, but is not limited to, methyl, ethyl,propyl, isopropyl, butyl, iso-butyl, sec-butyl, pentyl, 3-pentyl, hexyl,cyclopropyl, cyclobutyl cyclopentyl, cyclohexyl, and the like.

As used herein, the term “haloalkyl” refers to an alkyl group-,covalently bonded to the parent molecule through a —C— linkage, in whichone or more of the hydrogen atoms are replaced by halogen. Such groupsinclude, but are not limited to, chloromethyl, fluoromethyl,difluoromethyl, trifluoromethyl and 1-chloro-2-fluoromethyl,2-fluoroisobutyl. A haloalkyl may be substituted or unsubstituted.

As used herein, the term “halo” or “halogen” refers to F (fluoro), Cl(chloro), Br (bromo) or I (iodo).

As used herein, the term “mercapto” refers to an alkyl radicalcovalently bonded to the parent molecule through an —S— linkage.

As used herein, the term “cycloalkyl” refers to saturated aliphatic ringsystem having three to twenty carbon atoms. A cycloalkyl refers tomonocyclic and polycyclic saturated aliphatic ring system including, butnot limited to, cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl,bicyclo[4.4.0]decanyl, bicyclo[2.2.1]heptanyl, adamantyl, norbornyl, andthe like. In certain embodiments, a cycloalkyl comprises 3 to 20 carbonatoms (whenever it appears herein, a numerical range such as “3 to 20”refers to each integer in the given range; e.g., “3 to 20 carbon atoms”means that a cycloalkyl group may comprise only 3 carbon atoms, etc., upto and including 20 carbon atoms, although the term “cycloalkyl” alsoincludes instances where no numerical range of carbon atoms isdesignated). A cycloalkyl may be designated as “C₃-C₇ cycloalkyl” orsimilar designations. By way of example only, “C₃-C₆ cycloalkyl”indicates a cycloalkyl having two, three, four, five or six carbonatoms, e.g., the cycloalkyl is selected from cyclopropyl, cyclobutyl,cyclopentyl, and cyclohexyl.

As used herein, the term “alkoxy” refers to an alkyl radical covalentlybonded to the parent molecule through an —O— linkage. In someembodiments, alkoxys may be substituted or unsubstituted. Examples ofalkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy,isopropoxy, butoxy, n-butoxy, sec-butoxy, t-butoxy, cyclopropyloxy,cyclobutyloxy, cyclopentyloxy, cyclohexyloxy cycloheptyloxy, and thelike. In some embodiments, the alkoxy may have C1 to C10 carbon atoms.

As used herein, the term “alkenyl” refers to a radical of from two totwenty carbon atoms containing at least one carbon-carbon double bondincluding, but not limited to, 1-propenyl, 2-propenyl,2-methyl-1-propenyl, 1-butenyl, 2-butenyl, cyclopropenyl, cyclopentenyl,cyclohexenyl, cycloheptenyl and the like. In some embodiments, alkenylsmay be substituted or unsubstituted. In some embodiments, the alkenylmay have C2 to C4 carbon atoms. As used herein, the term “alkynyl group”refers to a monovalent straight or branched chain radical of from two totwenty carbon atoms containing at least one carbon-carbon triple bondincluding, but not limited to, 1-propynyl, 1-butynyl, 2-butynyl, and thelike. In some embodiments, alkynyls may be substituted or unsubstituted.In some embodiments, the alkynyl may have C2 to C4 carbon atoms.

As used herein, the term “aryl” refers to aromatic radical having onering and optionally an appended ring, or multiple fused rings. Examplesof aryl groups include, but are not limited to, phenyl, biphenyl,naphthyl, phenanthrenyl, naphthacenyl, and the like. In someembodiments, aryls may be substituted or unsubstituted. In someembodiments, the aryl can be a “heteroaryl” group.

As used herein, the term “heteroaryl” refers to an aromatic ring systemradical in which one or more ring atoms are not carbon, namelyheteroatom, having one ring or multiple fused rings. In fused ringsystems, the one or more heteroatoms may be present in only one of therings. Examples of heteroatoms include, but are not limited to, oxygen,sulfur and nitrogen. Examples of heteroaryl groups include, but are notlimited to, furanyl, thieny, imidazolyl, quinazolinyl, quinolinyl,isoquinolinyl, quinoxalinyl, pyridinyl, pyrrolyl, oxazolyl, indolyl, andthe like.

As used herein, the term “alkoxy” refers to straight or branched chainalkyl radical covalently bonded to the parent molecule through an —O—linkage. Examples of alkoxy groups include, but are not limited to,methoxy, ethoxy, propoxy, isopropoxy, butoxy, n-butoxy, sec-butoxy,t-butoxy and the like.

In some embodiments, the electrode current collector may be selectedfrom the group consisting of a metal such as aluminum, copper, nickel,silver or stainless steel, and alloys thereof. In some embodiments,aluminum or an aluminum alloy may be used as the electrode currentcollector. In some embodiments, the electrode current collector may begenerally formed to a thickness of 3 to 500 μm.

In some embodiments, the binder may include a secondary binder. In someembodiments, the secondary binder may be any material that improvesproperties of binding positive active material particles among oneanother and binding the positive active material with a currentcollector. Examples of the secondary binder include polyvinyl alcohol,carboxylmethyl cellulose, hydroxypropyl cellulose, polyvinyl chloride,carboxylated polyvinyl chloride, polyvinylfluoride, an ethyleneoxide-containing polymer, polyvinylpyrrolidone, polyurethane,polytetrafluoroethylene, polyvinylidene fluoride, polyethylene,polypropylene, a styrene-butadiene rubber, an acrylatedstyrene-butadiene rubber, an epoxy resin, nylon, and the like, but arenot limited thereto. In particular, polyvinylidene fluoride ispreferably used as the secondary binder

In some embodiments, the solvent may include a nonaqueous solvent or anaqueous solvent. Examples of the nonaqueous solvent may includeN-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide,N,N-dimethylaminopropylamine, ethyleneoxide, tetrahydrofuran, and thelike. The aqueous solvent may include water.

In some embodiments, the conductive agent may impart conductivity to anelectrode. In some embodiments, the conductive agent may include anyelectrically conductive material, unless it causes a chemical change,and may be added in an amount of 1 to 30 wt % based on the total weightof the electrode slurry. Examples of the conductive material include acarbon-based material or carbon nanotube (CNT), such as naturalgraphite, artificial graphite, carbon black, acetylene black, ketchenblack, a carbon fiber, and the like; a metal-based material such as ametal powder, a metal fiber, or the like that includes copper, nickel,aluminum, silver, and the like; a conductive polymer such as apolyphenylene derivative; or mixtures thereof.

In some embodiments, the negative electrode or the positive electrodemay further include a filler or a viscosity modifier according to thenecessity.

In some embodiments, the filler may be an auxiliary agent forsuppressing expansion of the electrode and any fibrous material may beused, unless it causes a chemical change to the battery. Examples of thefiller may include olefin-based polymers such as polyethylene orpolypropylene, and fibrous materials such as a glass fiber, a carbonfiber or a metal fiber.

In some embodiments, the viscosity modifier serves to control theviscosity of the electrode slurry to facilitate mixing of the electrodeslurry and coating of the slurry on the current collector, and may beadded in an amount of 30 wt % or less based on the total weight of theelectrode slurry. Examples of the viscosity modifier may includecarboxymethylcellulose, polyvinylidene fluoride, but not limitedthereto. In some embodiments, the solvent used in preparing the positiveelectrode slurry may also serve as the viscosity modifier.

Lithium Rechargeable Battery

Some embodiments provide a lithium rechargeable battery include anegative electrode, a positive electrode, a separator interposed betweenthe negative electrode and the positive electrode, and an electrolyte.

The separator prevents a short circuit between the positive electrodeand the negative electrode and provides a passageway of lithium ions. Insome embodiments, a polyolefin-based polymer film, such aspolypropylene, polyethylene, polyethylene/polypropylene,polyethylene/polypropylene/polyethylene,polypropylene/polyethylene/polypropylene, or a multilayered filmthereof, a microporous film or nonwoven fabric may be used as theseparator.

In some embodiments, a film formed by coating a highly stable resin onthe microporous polyolefin film may also be used as the separator. Whena solid electrolyte such as a polymer is used as the electrolyte, it mayalso serve as the separator.

In some embodiments, the electrolyte may include a lithium salt and anonaqueous organic solvent, and may further include additives forimproving charge and discharge characteristics or preventing overcharge.

The lithium salt plays a role of supplying lithium ions in a battery andoperating a basic operation of the rechargeable lithium battery. Thenonaqueous organic solvent serves as a medium that allows lithium ionsparticipating in electrochemical reactions of the battery to movebetween positive and negative electrodes therein.

Non-limiting examples of the lithium salt include at least one saltselected from LiPF₆, LiBF₄, LiSbF₆, LiAsF₆, LiClO₄, LiCF₃SO₃,LiN(SO₂CF₃)₂, LiN(SO₂C₂F₅)₂, LiC(SO₂CF₃)₃, LiN(SO₃CF₃)₂, LiC₄F₉SO₃,LiAlO₄, LiAlCl₄, LiCl and LiI. In some embodiments, the lithium salt maybe used in a concentration ranging from about 0.6 M to about 2.0 M,preferably ranging from about 0.7 M to about 1.6 M. When theconcentration of the lithium salt is less than 0.6 M, electrolyteconductivity may be lowered, resulting in deterioration of electrolyteperformance. When the concentration of the lithium salt is greater than2.0 M, electrolyte viscosity may increase, resulting in a reduction oflithium ion mobility.

In some embodiments, the nonaqueous organic solvent may includecarbonates, esters, ethers or ketones, which may be used alone or incombination. Examples of the carbonates may include dimethyl carbonate(DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropylcarbonate (MPC), ethylpropyl carbonate (EPC), methylethyl carbonate(MEC), ethylene carbonate (EC), propylene carbonate (PC), butylenecarbonate (BC), and the like, examples of the esters may includeγ-butyrolactone (GBL), n-methyl acetate, n-ethyl acetate, n-propylacetate, and the like, and examples of the ethers may include dibutylether, and the like, but not limited thereto.

Among the nonaqueous organic solvents, the carbonate-based solvent maybe prepared by mixing a cyclic carbonate and a chain carbonate. In someembodiments, the cyclic carbonate and the chain carbonate may be mixedtogether in a volume ratio ranging from about 1:1 to about 1:9. When themixture is used in the range of the volume ratio, the electrolyteperformance may preferably be enhanced.

In some embodiments, the non-aqueous organic electrolyte may be furtherprepared by mixing a carbonate-based solvent with an aromatichydrocarbon-based solvent. Specific examples of the aromatichydrocarbon-based organic solvent may include, but is not limited to, atleast one selected from benzene, fluorobenzene, bromobenzene,chlorobenzene, cyclohexylbenzene, isopropylbenzene, n-butylbenzene,octylbenzene, toluene, xylene, mesitylene, and the like, which may beused alone or in combination.

In some embodiments, the carbonate solvent and the aromatichydrocarbon-based organic solvent may be mixed together in a volumeratio ranging from about 1:1 to about 30:1 in the electrolyte includingthe carbonate solvent and the aromatic hydrocarbon-based organicsolvent. Within this range, desired electrolyte performance may bedemonstrated.

Hereinafter, the rechargeable battery including the electrode preparedaccording to an embodiment of the present disclosure will be describedin detail.

FIG. 1 is a partially cross-sectional view of a lithium rechargeablebattery according to an embodiment.

The following examples are provided for a better understanding of thepresent embodiments and technical details known in the related art areappropriately modified to be used as reference.

Referring to FIG. 1, the lithium rechargeable battery according to anembodiment includes a can 10, an electrode assembly 20, a cap assembly30 and an electrolyte. The lithium rechargeable battery may befabricated by accommodating the electrode assembly 20 and theelectrolyte in the can 10 and sealing a top end of the can 10 by the capassembly 30.

In some embodiments, the cap assembly 30 may include a cap plate 40, aninsulation plate 50, a terminal plate 60 and an electrode terminal 80.In some embodiments, the cap assembly 30 may be coupled to an insulationcase 70 to seal the can 10.

In some embodiments, the electrode terminal 80 may be inserted into aterminal hole 41 centrally formed in the cap plate 40. When theelectrode terminal 80 is inserted into the terminal hole 41, a tubulargasket 46 is coupled to an outer surface of the electrode terminal 80 tothen be inserted into the terminal hole 41. Therefore, the electrodeterminal 80 is electrically insulated from the cap plate 40.

In some embodiments, the electrolyte may be injected into the can 10through an electrolyte injection hole 42 after the cap assembly 30 isassembled to the top end of the can 10. In some embodiments, theelectrolyte injection hole 42 may be closed by a separate plug 43. Insome embodiments, the electrode terminal 80 may be connected to anegative electrode tab 17 of the negative electrode 23 or a positiveelectrode tab 16 of the positive electrode 21 to function as a negativeelectrode terminal or a positive electrode terminal.

In some embodiments, the rechargeable battery including the electrodeprepared as disclosed and described herein may be fabricated in acylindrical shape or a pouch shape as well as a prismatic shapeillustrated herein.

The following examples illustrate the present embodiments in moredetail. These examples, however, are not in any sense to be interpretedas limiting the scope of this disclosure.

PREPARATION EXAMPLE 1

To a 2 L reaction vessel equipped with a heater, a cooler and a stirrerwere added deionized (DI) water (1,830 g), polyvinyl alcohol (132 g) andammonium bicarbonate (0.3 g) to afford mixture A. The mixture was heatedat 80° C. under a nitrogen atmosphere and maintained at this temperaturefor 2 hours. A 2.5 wt % mixture of methyl(meth)acrylate (MMA, 61 g),butylacrylate (BAM, 63.7 g) and methacrylic acid (MAA, 3.96 g) was addedto a flask to afford mixture B. Mixture B was treated with a solutionobtained by dissolving ammonium persulfate (0.02 g) in DI water (5 g) toafford mixture C. Thereafter, mixture A and a solution obtained bydissolving ammonium persulfate (0.35 g) in DI water (20 g) weresimultaneously both added dropwise to mixture C over 2.5 hours. Aftercompletion of addition the reaction was maintained for 2 hours, theresultant product was cooled to 40° C. or less and packaged, yielding abinder having a weight average molecular weight of 320,000, a solidmatter content of 11.0%, pH of 5.4, and viscosity of 1,100 cps.

PREPARATION EXAMPLE 2

To a 2 L reaction vessel equipped with a heater, a cooler and a stirrerwere added DI water (1,830 g), polyvinyl alcohol (132 g) and ammoniumbicarbonate (0.3 g) to afford mixture A. The mixture was heated at 80°C. under a nitrogen atmosphere and maintained at this temperature for 2hours. A 2.5 wt % mixture of methyl(meth)acrylate (MMA, 61 g),butylacrylate (BAM, 63.7 g), methacrylic acid (MAA, 3.96 g) andN-methylol acrylamide (3.3 g) was added to a flask to afford mixture B.Mixture B was treated with a solution obtained by dissolving ammoniumpersulfate (0.02 g) in DI water (5 g) to afford mixture C. Thereafter,mixture A and a solution obtained by dissolving ammonium persulfate(0.35 g) in DI water (20 g) were simultaneously both added dropwise tomixture C over 2.5 hours. After completion of addition the reaction wasmaintained for 2 hours, the resultant product was cooled to 40° C. orless and packaged, yielding a binder having a weight average molecularweight of 330,000, a solid matter content of 11.0%, pH of 5.4, and aviscosity of 1,830 cps.

PREPARATION EXAMPLE 3

To a 2 L reaction vessel equipped with a heater, a cooler and a stirrerwere added DI water (1,430 g), polyvinyl alcohol (132 g) and ammoniumbicarbonate (0.3 g to afford mixture A. The mixture was heated at 80°under a nitrogen atmosphere and maintained at this temperature for 2hours. A 2.5 wt % mixture of methyl(meth)acrylate (MMA, 61 g),butylacrylate (BAM, 63.7 g) and methacrylic acid (MAA, 3.96 g) was addedto a flask to afford mixture B. Mixture B was treated with a solutionobtained by dissolving ammonium persulfate (0.02 g of) in DI water (5 g)to afford mixture C. Thereafter, mixture A a solution obtained bydissolving ammonium persulfate (0.35 g) in DI water (20 g) and a mixtureof dimethyldimethoxy silane (5.84 g), methyltrimethoxy silane (5.84 g)and 3-(meth)acryloxypropyl trimethoxy silane (1.31 g of) were all threesimultaneously added dropwise to mixture C over 2.5 hours. Aftercompletion of addition the reaction was maintained for 2 hours, theresultant product was cooled to 40° C. or less and packaged, yielding abinder having a weight average molecular weight of 325,000, a solidmatter content of 14.0%, pH of 5.1, and a viscosity of 3,700 cps.

PREPARATION EXAMPLE 4

To a 2 L reaction vessel equipped with a heater, a cooler and a stirrerwere added DI water (1,830 g), polyvinyl alcohol (132 g) and ammoniumbicarbonate (0.3 g to afford mixture A. The mixture was heated at 80° C.under a nitrogen atmosphere and maintained at this temperature for 2hours. A 2.5 wt % mixture of styrene (94 g), butylacrylate (BAM, 27 g),methacrylic acid (MAA, 4 g) and N-methylol acrylamide (7 g) was added toa flask to afford mixture B. Mixture B was treated with a solutionobtained by dissolving ammonium persulfate (0.02 g) in DI water (5 g) toafford mixture C. Thereafter, mixture A and a solution obtained bydissolving ammonium persulfate (0.35 g) in DI water (20 g) were bothsimultaneously added dropwise to mixture C over 2.5 hours. Aftercompletion of addition the reaction was maintained for 2 hours, theresultant product was cooled to 40° C. or less and packaged, yielding abinder having a weight average molecular weight of 380,000, a solidmatter content of 11.0%, pH of 5.5, and a viscosity of 1,720 cps.

EXPERIMENTAL EXAMPLE 1 Measurement of Physical Properties

Various physical properties of the binders prepared in PreparationExamples 1 to 4 were analyzed using the following measuring devices andthe measurement results are listed in Table 1.

Molecular weight: GPC (Gel Permeation Chromatography) (LC-10A instrumentmanufactured by Shimadzu, Japan).

Glass transition temperature: DSC (Differential Scanning calorimetry) (Q10 thermal analysis (TA) instrument.

TABLE 1 Glass transition Molecular weight temperature Functional monomerMn Mw (Tg) (° C.) type wt % Preparation 255,000 320,000 12.50, 79.30 — —Example 1 Preparation 270,000 330,000 12.74, 78.92 N-MOA 2.5 Example 2Preparation 221,000 325,000 10.32, 80.16 Silane 9.2 Example 3Preparation 275,000 380,000 69.08 N-MOA 5.3 Example 4

COMPARATIVE EXAMPLE 1

80 g of graphite as a negative electrode active material, 5 g of SBR(Styrene butadiene Rubber) and 5 g of CMC (carboxymethylcellose) as abinder, and 10 g of denka black as a conductive agent were dispersed inwater as a solvent to have a solid matter content of about 45%, therebypreparing a negative electrode slurry.

The negative electrode slurry was coated on a copper (Cu) foil and thendried to have a thickness of 111 μm, and compressed to prepare a 56 μmthick negative electrode.

The prepared negative electrode was cut in a shape of a coin having adiameter of 16 mm. A lithium rechargeable battery was manufactured usingthe negative electrode, a polypropylene separator, lithium metal as acounter electrode and an electrolyte prepared by dissolving 1.5 mol/L ofLiPF₆ in a mixture of ethylene carbonate (EC), fluoroethylene carbonate(FEC) and diethyl carbonate (DEC) in a volume ratio of 5:75:20.

COMPARATIVE EXAMPLE 2

As negative electrode active materials, 4 g of silicon oxide (SiO_(x))(x=1) and 76 g of a mixture containing graphite (MC08 manufactured byMitsubishi Chemical, Japan) and graphite (SD 13 manufactured by ShowaDenko, Japan) mixed in a weight ratio of 1:1; 5 g of SBR (Styrenebutadiene Rubber) and 5 g of CMC (carboxymethylcellose) as a binder; and10 g of denka black as a conductive agent were dispersed in water as asolvent to have a solid matter content of about 45%, thereby preparing anegative electrode slurry.

The negative electrode slurry was coated on a copper (Cu) foil and thendried to have a thickness of 111 μm, and compressed to prepare a 56 μmthick negative electrode.

The prepared negative electrode was cut in a shape of a coin having adiameter of 16 mm. A lithium rechargeable battery was manufactured usingthe negative electrode, a polypropylene separator, lithium metal as acounter electrode and an electrolyte prepared by dissolving 1.5 mol/L ofLiPF₆ in a mixture of ethylene carbonate (EC), fluoroethylene carbonate(FEC) and diethyl carbonate (DEC) in a volume ratio of 5:75:20.

COMPARATIVE EXAMPLE 3

A lithium rechargeable battery was manufactured in substantially thesame manner as in Comparative Example 1, except that 8 g of siliconoxide (SiO_(x)) (x=1) and 72 g of a mixture containing graphite (MC08manufactured by Mitsubishi Chemical, Japan) and graphite (SD 13manufactured by Showa Denko, Japan) in a weight ratio of 1:1 were usedas negative electrode active materials; that 5 g of SBR (Styrenebutadiene Rubber) and 5 g of CMC (carboxymethylcellose) were used asbinders; and that 10 g of denka black was used as a conductive agent.

COMPARATIVE EXAMPLE 4

A lithium rechargeable battery was manufactured in substantially thesame manner as in Comparative Example 1, except that 16 g of siliconoxide (SiO_(x)) (x=1) and 64 g of a mixture containing graphite (MC08manufactured by Mitsubishi Chemical, Japan) and graphite (SD 13manufactured by Showa Denko, Japan) in a weight ratio of 1:1 were usedas negative electrode active materials, and 10% PAI (Polyamide Imide)having a nonaqueous solvent NMP was used as a binder, and the resultantproduct was dried at 100° C., followed by performing heat treatment at350° C. for 2 hours.

EXAMPLE 1

A lithium rechargeable battery was manufactured in substantially thesame manner as in Comparative Example 1, except that 10 g of the polymerof Chemical Formula 4 prepared in Preparation Example 3 was used as abinder:

wherein L³ may be

wherein R₈ is H, CH₃, CH₃(CH₂)₃ or C₃H₆Si(OCH₃)₃ used in a ratio of3.1:46.9:49.0:1.0, and R₉ is H or CH₃ used in a ratio of 49:51.

EXAMPLE 2

A lithium rechargeable battery was manufactured in substantially thesame manner as in Comparative Example 2, except that 10 g of a polymerof Chemical Formula 4 was used as a binder.

EXAMPLE 3

A lithium rechargeable battery was manufactured in substantially thesame manner as in Comparative Example 1, except that 12 g of siliconoxide (SiO_(x)) (x=1) and 68 g of a mixture containing MC08 graphite andSD 13 graphite mixed in a weight ratio of 1:1 were used as negativeelectrode active materials and the polymer of Chemical Formula 4 wasused as a binder.

EXAMPLE 4

A lithium rechargeable battery was manufactured in substantially thesame manner as in Comparative Example 1, except that 16 g of siliconoxide (SiO_(x)) (x=1) and 64 g of a mixture containing MC08 graphite andSD 13 graphite mixed in a weight ratio of 1:1 were used as negativeelectrode active materials and the polymer of Chemical Formula 4 wasused as a binder.

EXPERIMENTAL EXAMPLE 1 Capacity Characteristics

The lithium rechargeable batteries manufactured in Comparative Examplesand Examples were charged and discharged under a constant current of 0.1C to then measure the discharge capacity of each battery, and themeasurement results are shown in Table 2. In measuring the capacity, thecut-off voltage was set to 1.5 V-0.01 V.

EXPERIMENTAL EXAMPLE 2 Retention Characteristics

Each of the lithium rechargeable batteries manufactured in ComparativeExamples and Examples was subjected to 50 cycle capacity tests under aconstant current of 1 C. The capacity retention (%) at a 50th cyclerelative to initial cycle capacity was measured and the results thereofare shown in Table 2.

EXPERIMENTAL EXAMPLE 3 Initial Efficiency

Charge and discharge capacities of each of the lithium rechargeablebatteries manufactured in Comparative Examples and Examples weremeasured after repeated charge and discharge cycles under a constantcurrent of 0.1 C. The discharge capacity (%) relative to the chargecapacity was measured as an initial capacity and the results thereof areshown in Table 2.

EXPERIMENTAL EXAMPLE 4 Adhesion

In order to evaluate adhesion properties of the negative electrodes ofthe lithium rechargeable batteries manufactured in Comparative Examplesand Examples, a peeling-off test was performed such that each 10×25 mmsample was fixed to a glass plate and an end of the negative electrodewas attached to a jig to then be lifted 15 mm at a speed of 100 mm/min,and the results thereof are shown in Table 2.

TABLE 2 Discharge Retention Initial capacity (%) efficiency Adhesion(mAh/g) @50 (%) (gf/mm) Comparative 458 84@50 73 8 Example 4 Example 1355 96@50 84 9.2 Example 2 420 94@50 85 8.5 Example 3 466 92@50 83 7.9Example 4 534 95@50 85 7.3

As shown in Table 2, in each of Examples 1 to 4 in which a binder of oneor more embodiments of the present disclosure was used, the negativeelectrode active material had very high adhesion. In addition, thelithium rechargeable battery prepared in Example 4 in which the amountof the Si-based active material was increased 2 to 4 times demonstrateda much better cycle life characteristic than in Comparative Example 4 inwhich PAI was used.

While the present embodiments have been described in connection withwhat is presently considered to be practical exemplary embodiments, itis to be understood that various modifications and equivalentarrangements may be made without departing from the spirit or scope ofthe present disclosure as set forth in the following claims.

What is claimed is:
 1. A binder for an electrode of a lithiumrechargeable battery, comprising a copolymer of Chemical Formula 1:

wherein L¹ is

wherein each R₁ is independently OH or —OR₅, wherein each R₂ isindependently selected from H (hydrogen), a substituted or unsubstitutedC₁-C₁₀ alkyl group, a substituted or unsubstituted styrene group,—(C(R₆)₂)_(q)OSi(R₆)₂OR₆, —(C(R₆)₂)_(q)OSi(R₆)₃, —(C(R₆)₂)_(q)OSi(OR₆)₃,—(C(R₆)₂) ,_(q)SiR₆(OR₆)₂, —(C(R₆)₂) ,_(q)Si(R₆)₂OR₆,—(C(R₆)₂)_(q)Si(R₆)₃ and —(C(R₆)₂) (_(q)Si(OR₆)₃, wherein each R₃ is acompound of Chemical Formula 3:—SiR₇R₇—[—O—SiR₇R₇—]_(p)—R₇  Chemical Formula 3 wherein at least one ofR₂ and R₃ is not H (hydrogen); wherein each R₄ is OR₁₀; wherein R₅ is—(CHR₂CR₃COR₄)_(m)(CHR₂CHR₃COR₄); wherein each R₆ is independentlyselected from H (hydrogen) or a substituted or unsubstituted C₁-C₂₀alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₁₆alkyl group, a C₆-C₂₀ aryl group, and a C₃-C₈ cycloalkyl group; whereineach R₇ is independently selected from H (hydrogen), OH, a substitutedor unsubstituted C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀alkynyl group, a C₆-C₂₀ aryl group, and a C₃-C₈ cycloalkyl group, eachoptionally substituted with one or more components selected from thegroup consisting of halogen, amino, mercapto, ether, ester, C₁-C₂₀alkoxy, sulfone, nitro, hydroxy, cyclobutene, carbonyl, carboxyl, alkyd,urethane, vinyl, nitrile, and epoxy; wherein each R₁₀ is a compound ofChemical Formula 3 as defined above; wherein each R₁₁ and R₁₂ isindependently H (hydrogen), a substituted or unsubstituted C₁-C₁₀straight or branched alkyl group, a substituted or unsubstituted C₂-C₂₀alkenyl group, or a substituted or unsubstituted C₃-C₈ cycloalkyl group;wherein x is an integer between 1 and 5,000, wherein each m is aninteger between 500 and 5,000, wherein each n is an integer between 500and 5,000; wherein each p is an integer between 500 and 5,000; whereineach q is 0, 1, 2, 3, 4, 5, or 6; and wherein R₅ is from 30 to 70 wt %of the molecular mass of the copolymer of Chemical Formula
 1. 2. Thebinder of claim 1, wherein the binder of Chemical Formula 1 has anaverage molecular weight of 200,000 to 500,000.
 3. The binder of claim1, wherein in the copolymer of Chemical Formula 1, n and x are containedin a ratio of 1:2.3 to 2.3:1.
 4. The binder of claim 1, wherein thebinder is made by a process comprising: grafting monomer to polyvinylalcohol, wherein the monomer is an acryl monomer and a carboxylicmonomer, where the acryl monomer is at least one selected from the groupconsisting of N-methylol acrylamide, methyl(meth)acrylate,butyl(meth)acrylate, ethyl acrylate,2-ethyl hexyl acrylate,hydroxypropyl(meth)acrylate, styrene, alpha-methyl styrene and(meth)acrylonitrile; and where the carboxylic monomer is at least oneselected from the group consisting of (meth)acrylic acid, itaconic acid,furmaric acid, crotonic acid, maleic acid, monomethyl itaconate, methylfumarate and monobutyl fumarate, which are used alone or in acombination of two or more of these materials.
 5. The binder of claim 4,wherein the acryl monomer is contained in an amount of 70 to 98 wt%based on the total weight of the monomers used.
 6. The binder of claim4, wherein the grafted acryl group has a glass transition temperature(Tg) in a range of 0 to 70° C.
 7. The binder of claim 4, furthercomprising a silane grafted binder.
 8. The binder of claim 1, furthercomprising a copolymer of Chemical Formula 2:

wherein L¹ is

wherein L² is

y is an integer from 1 to about 5000; and wherein R₂ and R₃ are eachindependently H (hydrogen), a substituted or unsubstituted C₁-C₁₀ alkylgroup, or a substituted or unsubstituted styrene group, provided atleast one of R₂ and R₃ is not H (hydrogen), and R₄ is H (hydrogen), asubstituted or unsubstituted C₁-C₁₀ linear or branched alkyl group, asubstituted or unsubstituted C₂-C₂₀ alkenyl group, or a substituted orunsubstituted C₃-C₈ cycloalkyl group.
 9. The binder of claim 1, whereineach R₇ is independently C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, aC₂-C₂₀ alkynyl group, a C₆-C₂₀ aryl group, or a C₃-C₈ cycloalkyl group,each optionally substituted with one or more components selected fromthe group consisting of halogen, amino, mercapto, ether, ester, C₁-C₂₀alkoxy, sulfone, nitro, hydroxy, cyclobutene, carboxyl, alkyd, urethane,vinyl, and nitrile.
 10. An active material for an electrode of arechargeable battery, comprising: an electrode active material; thebinder of claim 1; and a solvent.
 11. An electrode for a rechargeablebattery using the electrode active material of claim
 10. 12. Arechargeable battery comprising: a positive electrode; a negativeelectrode; and an electrolyte, wherein one of the positive electrode andthe negative electrode is the electrode of claim
 11. 13. Therechargeable battery of claim 12, wherein the electrode is a negativeelectrode.